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Circulating tumor cells (CTCs) can be used as important biomarkers to reflect the progress and malignancy of tumors. However, current CTC detection technologies have some limitations for clinical applications due to their complexity, low specificity and high cost. Herein, we develop a terahertz anti-resonance hollow core fiber (THz AR-HCF) biosensor for CTC detection. Through simulation and experiment comparisons, the low-loss property of the THz AR-HCF is verified, and a suitable fiber is selected for biosensing applications. By measuring different cell numbers and different types of cancer cells, a good linear relationship between THz transmittance and the numbers of cells between 10 and 106 was found. Meanwhile, different types of tumor cells can be distinguished by comparing THz transmission spectra, indicating that the biosensor has high sensitivity and specificity for CTC detection. The biosensor only required a small amount of sample, as low as 100 μl, and enables label-free and nondestructive quantitative detection. Flow cytometry results showed that the cell viability was as high as 98.5±0.26% after whole assay process and there was no statistically significant difference compared with the negative control. This study demonstrated that the proposed THz AR-HCF has great potential for highly sensitive, label-free and nondestructive detection of CTCs in clinical samples.

Graphene is a two-dimensional material with unique physical and chemical properties, whose excellent biocompatibility has also attracted widespread attention in the field of biosensing and medical detection. Graphene provides a novel solution for dramatically improving the sensitivity of terahertz metasurface sensors, since the electrical conductivity can be modified by contact with biomolecules. In this paper, a metal-graphene hybrid metasurface is proposed and demonstrated for high-sensitive nortriptyline sensing based on the plasmon-induced transparency (PIT) resonances. The π-π stacks between nortriptyline and graphene lead to an increase in the Fermi level of graphene and a decrease in the conductivity, thus enhancing the PIT resonance. Experimental results show that the peak-to-peak amplitude magnitude of the PIT window is enhanced up to 3.4-fold with 1 ng nortriptyline analyte, and the minimum detection limit is extended down to 0.1 ng. But no significant change is observed from the samples without graphene as a comparative experiment, which demonstrates that the presence of graphene greatly enhances the bonding to the drug molecules and improves the sensing sensitivity. This metasurface sensor has the advantages of high sensitivity, fast detection speed, label-free and steady properties, which has potential applications in the fields of trace molecular sensing and disease diagnosis.

Metamaterial-inspired terahertz (THz) biosensors are devoted to developing high-sensitivity and label-free biosensing strategies. However, most meaningful molecular signals are obscured by the strong THz absorption of solvent water. Most reported THz biosensors require the tested samples to be tediously dried or replaced with a low-absorption medium, which impairs the original bioactivity and the distribution homogeneity of targets. As described in this proposed strategy, a molecule-specific THz biosensor was fabricated from an aptamer hydrogel-functionalized THz metamaterial. Benefitting from the strong interaction with the localized electric field of the metamaterial, trace thrombin-induced variations in the hydration state of the hydrogel can be sensitively probed, which was investigated experimentally and theoretically. The optimized THz biosensor exhibited remarkable specificity for actual serum sample assays and excellent sensitivity, with a relatively low detection limit of 0.40 pM in the human serum matrix. The proposed strategy could serve as a model system to develop various molecule-specific THz biosensors for aqueous molecule sensing.

Logistic regression (LR) is a supervised multiple linear regression model, which uses linear weighted calculation for input to obtain weight coefficients of model. The surface enhanced Raman spectroscopy (SERS) technology greatly enhances the Raman signal of analyte. LR model was used to analyze the data of seven types of pancreatic cancer-related miRNAs obtained from commercial SERS substrate. The classification ability of the model on such data was observed under the configurations of different key parameters (classification mode, regularization method and loss function optimization way), and the effect of the two types of data formats were also evaluated. The results showed that though LR model used to classify this data did not perform well as expected, miRNA-191 and miRNA-4306 still had high recalls (sensitivity), which laid a theoretical foundation for the purpose of using LR model to identify these two miRNAs to jointly diagnose of pancreatic cancer at miRNA level.

A highly sensitive method for detecting Staphylococcus aureus (S. aureus) is urgently needed to reduce the impact and spread of hospital-acquired infections and food-borne illness. For this purpose, this paper presents a THz metamaterial biosensor based on gold nanoparticles (AuNPs) and rolling circle amplification (RCA). The RCA process amplified the S. aureus DNA fragments and generated copious yields of long single-strand DNA molecules. These molecules were then conjugated with the AuNPs to form complexes that delivered exceptional increases in the refractive indices of the samples, and resulted in corresponding improvements in the THz response of the metamaterial. Under optimal conditions, the shifts in the metamaterial's resonance frequency displayed a linear relationship with concentrations of synthetic S. aureus DNA in the range from 10 fM to 10 pM, with a limit of detection of 2.77 fM. We also tested the practical application of this biosensor in measurements of genomic DNA in clinical bacterial strains, where the sensor showed a detection limit of 0.08 pg μL−1 and a linear range from 0.1 to 5 pg μL−1. It also exhibited reasonable specificity, resisting interference from three other pathogenic bacteria. These findings indicate that the proposed approach offers a cost-effective THz biosensing strategy that can be easily fabricated and conveniently operated to aid the diagnosis of infectious disease and food safety control.

Numerous studies have shown that exosomes are closely related to the pathogenesis of various diseases, especially cancers. Therefore, a rapid and sensitive method for exosome detection will be of great importance for the diagnosis and prognosis of diseases. We report here a method for exosome detection based on the CD63 aptamer and clustered regular interspaced short palindromic repeats (CRISPR)/Cas12a system. This method consists mainly of exosomal membrane protein recognition based on the CD63 aptamer and signal amplification based on CRISPR/Cas12a. The CD63 aptamer, as an easily adaptable nucleic acid strand, is responsible for the conversion of the amounts of exosomes into nucleic acid detection, whereas CRISPR/Cas12a is responsible for highly specific nucleic acid signal amplification. The detection range of the method was determined as 3 × 103-6 × 107 particles per microliter. Additionally, we successfully applied this method to detect exosomes in clinical samples from both healthy individuals and patients with lung cancer, and the results were highly consistent with those obtained by nanoparticle tracking analysis. In general, this method provides a highly sensitive and specific method for the detection of exosomes and offers an avenue toward future exosome-based diagnosis of diseases.

Sensitive and specific detection of microRNAs (miRNAs) is of critical significance for early diagnosis of cancers such as pancreatic cancer with atypical initial symptoms and high mortality. Despite exponential amplification reaction (EXPAR) is an attractive isothermal amplification method for detecting miRNAs, it faces the problems of the dependence difference and low specificity. To address such challenges, herein, a nicking-assisted entropy-driven DNA circuit triggered exponential amplification reaction (NAED-EXPAR) was firstly employed for ultrasensitive and specific detection of miRNA in "one-pot" manner at constant temperature. Nicking-assisted entropy-driven DNA circuit can specifically recognize the target miRNA, leading to continuous disassembly of DNA substrates via intramolecular toehold-mediated branch migration. During the reaction, the catalytic circuit can consume excess fuel DNA strands to produce a large number of primers. Then the newly formed primers can trigger EXPAR for highly efficient signal amplification. Mechanism analysis shows that the amplification efficiency of NAED-EXPAR is superior than that of single EXPAR. For miR-21, the detection limit of NAED-EXPAR can reach 100 aM, which is at least five orders of magnitude higher than the standard EXPAR that directly uses the target as primer. NAED-EXPAR shows improved specificity for identifying single nucleotide variations and enables sensitive and accurate analysis of miR-21 in human cancer cell lines. This method is expected to offer a new approach for the reliable quantification of miRNAs in complex biological matrices and provide valuable information for early cancer diagnosis.

Proinflammatory cytokines play a causal role in the development of hyperinsulinemia and T2MD. FOXO1, a transcription factor which is known to enhance proinflammation, was recently shown to be involved in obesity-induced β cell dysfunction. However, molecular mechanisms for the association remained elusive. In this study, we first found that both leptin (10 nM) and TNF-α (20 ng/ml) significantly inhibited glucose-stimulated insulin secretion (GSIS) of INS-1E cells. When in combination, the GSIS function of INS-1E cells was significantly increased compared with that of the leptin alone treatment, indicating that TNF-α attenuated the inhibiting effect of leptin on GSIS of INS-1E cells. Similarly, we found that TNF-α has the same inhibitory effect on leptin in regulating insulin synthesis and secretion, and the survival and apoptosis of insulin cells. Further studies showed that TNF-α blocks leptin pathway by reducing the expression of leptin receptor (LepRb, also called OBRb) and inhibiting the activation of STAT3, a key molecule involved in the leptin signaling pathway in INS-1E cells. Besides, the downregulated expression of phosphorylated FOXO1 was found to be involved in the possible mechanism of TNF-α. Overexpression of constitutively active FOXO1 markedly aggravated the LepRb reduction by TNF-α treatment of INS-1E cells, and the endogenous FOXO1 knockdown abolished the effect of TNF-α on INS-1E cells. Furthermore, we have proved that FOXO1 could directly bind to the promoter of LepRb as a negative transcription regulator. Taken together, the results of this study reveal that TNF-α-induced LepRb downregulated in pancreatic β cells and demonstrate that transcriptional reduction of FOXO1 might be the primary mechanism underlying TNF-α promoting INS-1E leptin resistance and β cell dysfunction. Conclusions. Our current studies based on INS-1E cells in vitro indicate that the inflammatory factor TNF-α plays an important role in the development of INS-1E leptin resistance and glucose metabolism disorders, probably through FOXO1-induced transcription reduction of LepRb promoter in pancreatic β cells, and FOXO1 may be a novel target for treating β cell dysfunction in obesity-induced hyperinsulinemia and T2DM.

Objective Macrophage migration inhibitory factor (MIF) is an inflammatory and neurorendocrine mediator that counterregulates glucocorticoid immunosuppression. MIF polymorphisms, which comprise a variant promoter microsatellite (-794 CATT5-8 ), are linked genetically to autoimmune disease severity and to glucocorticoid resistance. While invasive stimuli increase MIF expression, MIF also is up-regulated by glucocorticoids, which serve as a physiologic regulator of inflammatory responses. This study was undertaken to define interactions between the MIF promoter, the glucocorticoid receptor (GR), and the transcription factor inverted CCAAT box binding protein 90 kd (ICBP90) (also referred to as UHRF1), which binds to the promoter in a -794 CATT5-8 length-dependent manner, to regulate MIF transcription. Methods Interactions of ICBP90, GR, and activator protein 1 (AP-1) with MIF -794 CATT5-8 promoter constructs were assessed by coimmunoprecipitation, Western blotting, and genetic knockdown. Nuclear colocalization studies were performed using anti-transcription factor antibodies and confocal microscopy of glucocorticoid-treated cells. MIF transcription was studied in CEM-C7 T cells, and the impact of the MIF -794 CATT5-8 microsatellite variation confirmed in peripheral blood T cells and in rheumatoid synovial fibroblasts of defined MIF genotype. Functional interactions were quantified by apoptosis and apoptotic signaling in high- and low-genotypic MIF-expressing human cells. Results We defined functional interactions between the transcription factors ICBP90, the GR, and AP-1 that up-regulated MIF transcription in a -794 CATT5-8 length-dependent manner. Experimental reduction of ICBP90, GR, or AP-1 decreased MIF expression and increased glucocorticoid sensitivity, leading to enhanced apoptosis in T lymphocytes and in rheumatoid synovial fibroblasts. Conclusion These findings suggest a mechanism for genetic variation of glucocorticoid-regulated MIF transcription, with implications for autoimmune disease severity and glucocorticoid responsiveness.

Gastric cancer (GC) is the fifth most common cancer in the world and a serious threat to human health. Due to its high morbidity and mortality, a simple, rapid and accurate early screening method for GC is urgently needed. In this study, the potential of Raman spectroscopy combined with different machine learning methods was explored to distinguish serum samples from GC patients and healthy controls. Serum Raman spectra were collected from 109 patients with GC (including 35 in stage I, 14 in stage II, 35 in stage III, and 25 in stage IV) and 104 healthy volunteers matched for age, presenting for a routine physical examination. We analyzed the difference in serum metabolism between GC patients and healthy people through a comparative study of the average Raman spectra of the two groups. Four machine learning methods, one-dimensional convolutional neural network, random forest, support vector machine, and K-nearest neighbor were used to explore identifying two sets of Raman spectral data. The classification model was established by using 70% of the data as a training set and 30% as a test set. Using unseen data to test the model, the RF model yielded an accuracy of 92.8%, and the sensitivity and specificity were 94.7% and 90.8%. The performance of the RF model was further confirmed by the receiver operating characteristic (ROC) curve, with an area under the curve (AUC) of 0.9199. This exploratory work shows that serum Raman spectroscopy combined with RF has great potential in the machine-assisted classification of GC, and is expected to provide a non-destructive and convenient technology for the screening of GC patients.

We demonstrate the THz near-field nano-imaging of Bacillus cereus and Corona Virus Disease 2019 (COVID-19) spike fake virus utilizing THz scattering near-field optical microscopy (SNOM). Here, it shows that bacteria and virus can be distinguished from other substances by THz near-field imaging. And we can use the THz time-domain spectrometer (TDS) scattering near field microscope(s-SNOM) to obtain the spectrum of different substances (bacteria and their substrate), then analyzing the differences between them from their specific responses in THz. This is of great significance to development of the terahertz near-field biology.

International audience; We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced. We demonstrate that the aptamer orientation and thus its flexibility rely strongly on the presence of a spacer of 15 thymines and on the experimental conditions with the aptamer lying on the surface in air and standing in the buffer. We reveal for the first time that the interaction with MnSOD induces a large loss of flexibility and freezes the aptamer structure in a single conformation.

Proinflammatory cytokines play a causal role in the development of hyperinsulinemia and T2MD. FOXO1, a transcription factor which is known to enhance proinflammation, was recently shown to be involved in obesity-induced

Based on high sensitivity, specific fingerprinting spectra and real-time detection, surface-enhanced Raman spectroscopy (SERS) is a powerful tool for the observation, the detection and the identification of chemical or biological species at low concentrations. One of the key elements for the SERS detection is the choice of SERS substrate. This latter one can be either a home-made one or either commercially purchased. For researchers who don’t have facilities to fabricate SERS substrates, the commercial ones are a necessary and optimal choice. Thus, a comprehensive evaluation of their reproducibility is urgently needed and carried out in this paper. The blank spectra as well as the SERS spectra of three probes molecules (4-mercaptobenzoic acid (4-MBA), 1, 2-bis (4-pyridyl) ethylene (BPE) and methylene blue (MB)) were analysed for two excitation wavelengths (532 and 785 nm). The most suitable detection condition was determined for each substrate. Under the optimum conditions, the SERS mapping were carried to measure the relative standard deviations (RSDs) to further evaluate the reproducibility of the substrates. The results demonstrated that the Enspectrc, Q-SERSTM and Hamamatsu substrates were the more suitable for reproducible SERS measurements.

Prospective testing for variants in the thiopurine S-methyltransferase (TPMT) is considered a key process in the development of thiopurine therapy. This testing is done to avoid toxicity and side effects in the management of diverse immunological and malignant conditions. Real-time fluorescent PCR techniques using duplex-crossed allele-specific primers in a single tube (DCAS-PCR) were developed in this study to genotype the common loss-of-function TPMT*3B c.460G > A (rs1800460) and TPMT*3C c.719A > G (rs1142345) usually occurring in individuals of Chinese ethnicity. In this method, several integrated strategies were used to completely eliminate the non-specific amplification that is commonly presented in traditional allele-specific (AS) PCR. These strategies include using AS-primers (ASP) that both are artificially mismatched in the penultimate positions and phosphorothioate modifications in the 5′-termini positions. In the assay, an AS-blocker was used, locus-specific TaqMan (LST) probes were used and we used at least two fragments were simultaneously amplified in a single tube which satisfy the thermodynamic characteristics of DNA polymerase to eliminate non-specific amplification. In a group of 200 unselected subjects, the results showed that 8 samples were heterozygous of TPMT*3C, and all samples possessed wild-type TPMT*3B. There was no non-specific amplification, and the genotypes were 100% consistent with Sanger sequencing.

Deoxyribonucleic acid (DNA) detection is essential for the accurate and early diagnosis of a disease. In this study, a femtomolar DNA detection method based on the exploitation of the localized surface plasmon (LSP) resonance of gold nanoparticles (AuNPs) was developed. We prepared Poly Ethylen Glycol (PEG) functionalized AuNPs with a specific DNA capture probe (CP) directly modified on the gold surface. Two strategies are proposed using different kinds of CP to detect the target DNA (tDNA). In the first strategy, CP is the complementary of the complete sequence of the DNA (CCP method). For the second strategy, we used two CPs, which were half complementary to tDNA, and these were hybridized with tDNA to form sandwich structures (MIX method). The results showed that our detection methods are highly sensitive and that the limits of detection of 124 am and 2.54 fm tDNA can be reached when using the CCP and MIX methods, respectively. In addition, the specificity of our two strategies is also demonstrated with mismatched DNAs. The proposed method provides a simple, fast, sensitive and specific DNA biosensor, which has the potential to be used for point-of-care tests (POCT).

Molecular machines constructed by three-dimensional (3-D) DNA walker have emerged as a hot topic in applications such as novel biosensors, cargo delivery platforms and intracellular imaging. Herein, we first propose a lame DNA walker that can randomly and autonomously move on microsphere-based 3-D track. The stochastic lame walker has a long leg mainly responsible for persistent movement and a short leg cutting substrates rapidly. Its motion is propelled by a nicking endonuclease cleavage of hybridized DNA tracks. Kinetic and persistent study show that the lame DNA walker enables reaction equilibrium at 30 min, need a cleat domain of at least 14 nucleotides and can persistently move on 3-D tracks with an average rate of 6.467 × 10−11 M s−1. We also demonstrate that the lame walker can be used to detect target DNA in the detection range of 10 pM–5 nM with high specificity by toehold exchange mechanism. This work will further expand the performance of 3-D DNA walkers and substantially contributes to the improved understanding of DNA walking systems.

MiRNA-150, a gene regulator that has been revealed to be abnormal expression in non-small cell lung cancer ( NSCLC ), can be regarded as a serum indicator for diagnosis and monitoring of NSCLC . Herein, a new sort of nanoprobe, termed allosteric spherical nanoprobe, was first developed to sense miRNA-150. Compared with conventional hairpin, this new nanoprobe possesses more enrichment capacity and reaction cross section. Structurally, it consists of magnetic nanoparticles and dual-hairpin. In the absence of miRNA-150, the spherical nanoprobes form hairpin structure through DNA self-assembly, which could promote the Förster resonance energy transfer (FRET) of fluorophore (FAM) and quencher (BHQ1) nearby. However, in the presence of target, the target-probe hybridization can open the hairpin and form the active “Y” structure which separated fluorophore and quencher to yield a “signal on” fluorescence. In the manner of multipoint fluorescence detection , the target-bound allosteric spherical nanoprobe could provide a high detection sensitivity with a linear range of 100 fM to 10 nM and a detection limit of 38 fM. More importantly, the proposed method could distinguish the expression of serum miRNA-150 among NSCLC patients and healthy people. Finally, we hoped that the potential bioanalytical application of this nanoprobe strategy will pave the way for point-of-care testing (POCT).

Terahertz (THz) spectroscopy has drawn great interest for the functional and conformational investigations of nucleic acids, but its intrinsic sensitivity hinders potential bio-sensing applications. Here, a novel THz biosensor was developed for detecting microRNA (miRNA) samples based on metamaterials coupled with nanoparticles and strand displacement amplification (SDA). In this method, the SDA reaction amplifies the target miRNA and generates copious yields of secondary DNA molecules (Trigger DNA), which are subsequently conjugated to metallic nanoparticles that form nanoparticle-Trigger DNA complexes. These complexes produce remarkable frequency shifts of metamaterials when linked to a large refractive index metallic nanoparticle like Au. The dependence of the metamaterial resonance on the nanoparticle diameter and metal type was investigated experimentally and theoretically. Under optimal conditions, the THz metamaterial biosensor presents good detection sensitivity with a limit of detection of 14.54 aM and exhibits a linear response for miRNA-21 at a concentration range from 1 fM to 10 pM. By measuring the miRNA-21 in spiked clinical serum samples, the sample recoveries were determined to be in the range between 90.92% and 107.01%. These findings demonstrate that the novel THz biosensor offers the capability for highly sensitive miRNA detection, with noteworthy potential applications in nucleic acid analysis and cancer diagnosis.

MiRNA-150, a gene regulator that has been revealed to be abnormal expression in non-small cell lung cancer (NSCLC), can be regarded as a serum indicator for diagnosis and monitoring of NSCLC. Herein, a new sort of nanoprobe, termed allosteric spherical nanoprobe, was first developed to sense miRNA-150. Compared with conventional hairpin, this new nanoprobe possesses more enrichment capacity and reaction cross section. Structurally, it consists of magnetic nanoparticles and dual-hairpin. In the absence of miRNA-150, the spherical nanoprobes form hairpin structure through DNA self-assembly, which could promote the Förster resonance energy transfer (FRET) of fluorophore (FAM) and quencher (BHQ1) nearby. However, in the presence of target, the target-probe hybridization can open the hairpin and form the active “Y” structure which separated fluorophore and quencher to yield a “signal on” fluorescence. In the manner of multipoint fluorescence detection, the target-bound allosteric spherical nanoprobe could provide a high detection sensitivity with a linear range of 100 fM to 10 nM and a detection limit of 38 fM. More importantly, the proposed method can distinguish the expression of serum miRNA-150 among NSCLC patients and healthy people. Finally, we hoped that the potential bioanalytical application of this nanoprobe strategy will pave the way for point-of-care testing (POCT).

In situ spatiotemporal microRNA (miRNA) imaging in mammal cells plays an essential role in illustrating its structures and biological functions. Herein, we proposed a near-infrared (NIR) light-activated nanoprobe for high-sensitive in situ controllable miRNA imaging in living cells. The NIR-activated nanoprobe employed an upconversion nanoparticle that acted as a NIR-to-UV transducer to trigger the following photocleavage toward a dumbbell DNA probe tethered on the surface of the nanoparticle. The structure change of the dumbbell probe then induced a catalytic hairpin assembly of target miRNAs, by which in situ readout of the amplified fluorescence signal was enabled. Additionally, both intracellular miRNA imaging and accurate quantification in live cells were realized without damaging the cell membranes. Compared with conventional in situ strategies, the proposed approach remarkedly increases imaging efficiency by eliminating those unfavored intercellular molecular imaging backgrounds. We assured that the proposed NIR-activated miRNA sensing strategy will add to the advancement for bioanalysis in living systems, which is of crucial importance in the diagnosis of various human diseases, especially cancers.

Cancer, especially malignant tumors with poor prognosis, has become a major hazard to human life and health. The tumor microenvironment is gaining increasing attention from researchers, as it offers a new focus for tumor diagnosis, therapy, and prognosis. The numbers of immune and stromal cells, which are major components of the tumor microenvironment, could be determined from RNA-seq data with the Estimation of STromal and Immune cells in Malignant Tumors using Expression data (ESTIMATE) algorithm. To explore the effects of immune and stromal cells on tumor prognosis, we analyzed associations between overall survival and immune/stromal scores for 20 malignant tumor types based on The Cancer Genome Atlas (TCGA) data. For six of the 20 tumor types, we observed statistically significant associations. Furthermore, to better explain the predictive ability of these scores, differentially expressed genes (DEGs) were identified in groups of cases with high or low immune or stromal scores for each of these six malignant tumor types. In addition, a list of immune-related genes was screened to identify prognostic predictors for one or more tumor types. Thus, multi-database joint analysis can provide a new approach to the assessment of tumor prognosis and allow the identification of related genes that may be new biomarkers for tumor metastasis and prognosis.

Modular DNA intelligent machines for detection and regulation of intracellular microRNAs., MicroRNAs (miRNAs) as novel biological targets are hardly applied in diagnostic and treatment of diseases, as they are difficult to be accurately detected and regulated. Here, we demonstrated a modular DNA intelligent machine named three-dimensional tweezers (TD-tweezers) to image and regulate miRNAs in living cells simultaneously. Fluorophore or miRNA inhibitors are introduced as detecting or regulating parts to construct different types of TD-tweezers, and the conformational state of TD-tweezers is controlled by the target miRNAs. The TD-tweezers exhibit excellent sensitivity, specificity, stability, and biocompatibility in vitro and in vivo, and their function of regulating miRNAs was confirmed by the up-regulated expression of downstream genes and proteins. Moreover, the TD-tweezers have been tested in whole blood, preliminarily verifying their clinical application potential. This design provides a multifunctional platform that can achieve efficient detection and regulation of targets within living cells and promote the development of DNA intelligent machines.

Increasing acidity is a promising method for bacterial inactivation by inhibiting the synthesis of intracellular proteins at low pH. However, conventional ways of pH control are not reversible, which can cause continuous changes in cellular and biological behaviours and are harmful to the host. Utilizing a photoacid that can reversibly alter pH over two units, we demonstrated a strong bacterial inhibition assisted by visible light. The pH value of the solution reverts back to the original level immediately after the irradiation is stopped. If a photoacid is combined with colistin, the minimum inhibitory concentration (MIC) of colistin on multidrug-resistant (MDR) Pseudomonas aeruginosa can be improved ∼32 times (from 8 to 0.25 μg mL−1), which significantly decreases the toxicity of colistin in clinics. Evidenced by the extremely low toxicity of the photoacid, this strategy is promising in MDR bacteria killing.

A highly sensitive method for detecting

Accurate identification of exosomes plays an essential role in facilitating disease diagnosis and therapies. Herein, we proposed an Aptamer-cholesterol-mediated Proximity Ligation Assay (AcmPLA) for accurate identification of exosomes in a dual-probe strategy, one aptamer probe for recognition of exosomal innate surface protein CD63 and another cholesterol probe for biolipid layer targeting. By integrating a proximity ligation of probes bound with exosomal biomarkers for specific recognition and a rolling circle amplification (RCA) strategy for signal amplification, we have successfully developed an exosomes-surface approach that can perform "AND" logic analysis of dual biomarkers, which not only could be used for exosomes quantification, but also for exosomes tracing. Besides RCA-initiated signal amplification, CD9 antibody-labeled magnetic beads were used to capture exosomes for isolation and secondary signal enrichment. Our approach can achieve specific exosomes isolation and accurate identification and thus could be exploited for broad applications in biological science, biomedical engineering, and personalized medicine.

Additional file 1: Fig S1. Schematic diagram of microarray structure. Table S1. Alignment of sequences used in experiment. Table S2. Comparison of the reported chemosensors for miRNA.

Objective: To evaluate the diagnostic value of fluorescence in situ hybridization (FISH) in bladder cancer. Methods: We enrolled healthy volunteers and patients who were clinically suspected to have bladder cancer and conducted FISH tests and cytology examinations from August 2007 to December 2008. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) values were calculated for both the FISH and urine cytology tests. Results: A cohort of 988 healthy volunteers was enrolled to establish a reference range for the normal population. A total of 4807 patients with hematuria were prospectively, randomly enrolled for the simultaneous analysis of urine cytology, FISH testing, and a final diagnosis as determined by the pathologic findings of a biopsy or a surgically-excised specimen. Overall, the sensitivity of FISH in detecting transitional-cell carcinoma was 82.7%, while that of cytology was 33.4% (p

Surface-enhanced Raman scattering (SERS) is a mature vibrational spectroscopic technique, and its application in chemical, material, especially life sciences is increasing rapidly. SERS alone cannot meet the demands of current analysis, while the desirable features of nucleic acid isothermal amplification (NAIA) make the simple, economical and flexible SERS become a reality. SERS has been combined with NAIA to provide researchers with more sensitive and precise analysis specifications in biological samples. However, there is no comprehensive review of the SERS analysis combined with NAIA yet. The present review introduces the development of SERS briefly and summarizes the necessary theory for understanding SERS and NAIA. The SERS analyses integrated with NAIA are the centerpiece of this review. They cover a broad range of topics, for example, hybridization chain reaction (HCR), catalytic hairpin assembly (CHA), entropy-driven catalytic reaction (EDR), strand displacement amplification (SDA), recombinase polymerase amplification (RPA), exponential amplification reaction (EXPAR), rolling circle amplification (RCA), and loop-mediated isothermal amplification (LAMP). In the end, the challenges and prospective opinions of the SERS in application are discussed.

Exosomal microRNA (miRNA) is a promising non-invasive biomarker for liquid biopsies. Herein, we fabricated a terahertz (THz) metamaterial biosensor that comprises an array of gold (Au) discs surrounded by annular grooves for exosomal miRNA assays based on duplex-specific nuclease (DSN)-triggered rolling circle amplification (RCA). In this strategy, the target miRNA is captured by a probe P0 immobilized on magnetic beads (MBs); it then repeatedly releases a primer P1 under the action of DSN, which acts as a highly specific initiator of the subsequent RCA step utilizing biotin-dUTP. After target recycling and nucleic acid amplification, the biotinylated amplification products were captured by the streptavidin (SA)-functionalized THz metamaterials, and further conjugated to SA-modified AuNPs that permit formation of a trimeric complex of SA-biotinylated RCA products-AuNP. The complex population scales with the starting concentration of the target miR-21, resulting in a red shift of the resonance peak of the THz metamaterials. This biosensor can lead to highly specific and sensitive detection with one-base mismatch discrimination and a limit of detection (LOD) down to 84 aM. Significant distinctions are seen in the frequency shifts for exosomal miR-21 quantitation in clinical plasma samples between pancreatic cancer patients and healthy controls. The frequency shifts of the THz metamaterials are consistent versus the reverse transcription-polymerase chain reaction (RT-PCR) results, illustrating the applicability and accuracy of our assay in real clinical samples.

Graphene quantum dots (GQDs)-based nanohybrid materials have gained great attention in multiple research applications, particularly in biomedical fields due to their unique physicochemical properties and outstanding biocompatibility compared to other nanomaterials. In this review, we focus on the most recent emerging developments including synthesis methods, in vivo imaging and in vitro biosensing applications. We also discuss these unresolved problematic and controversial issues facing their biomedical applications. Consequently, trends in approaches to improve the analytical performance of GQDs-based nanomaterials have also been put forward. Keywords: Graphene quantum dots (GQDs), Immunosensors, Imaging, Drug delivery, Toxicity